System and method for powering accessories in a hybrid vehicle

ABSTRACT

A heavy-duty hybrid vehicle power system includes a main power unit located in an engine compartment; an electric propulsion motor; a DC bus that receives DC power from the main power unit; a vehicle accessory traditionally powered directly from an internal combustion engine of a conventional heavy-duty vehicle and requiring more than 1 kilowatt of power; an electric accessory motor, which is electrically coupled with the DC bus and mechanically coupled with the vehicle accessory, configured to supply power to the vehicle accessory, and the electric accessory motor and vehicle accessory carried by the heavy-duty vehicle either inside or outside of the engine compartment; and at least one of an ultracapacitor pack and a fly wheel coupled with the DC bus and configured to store power when the main power unit is on and supply power in place of the main power unit when the main power unit is off.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 11/250,865, filed Oct. 14, 2005, which is a divisionalapplication of U.S. patent application Ser. No. 10/160,877, filed May31, 2002, now U.S. Pat. No. 7,119,454 issued Oct. 10, 2006, which areall hereby incorporated by in their entirety by reference.

FIELD OF THE INVENTION

The field of the present invention is generally motor vehicles, and inparticular systems within motor vehicles that power vehicle accessories.

BACKGROUND

In conventional vehicles, i.e., vehicles that are neither hybridvehicles nor electric vehicles, accessories such as hydraulic pumps,water pumps, vacuum pumps, and compressors for air brakes or airconditioning systems are powered directly from the internal combustionengine. The power required by these accessories may be steady overextended periods of time, as in the case of a water pump that is used tohelp cool the engine, or it may be required in short bursts when neededby the accessory, as in the case of hydraulic accessories or air brakes.Because such accessories have relatively high power requirements, themost economical and efficient source of power for these accessories isthe internal combustion engine.

In hybrid vehicles that include an internal combustion engine, either inseries or in parallel with the electric motor, these same accessoriesare often powered from the internal combustion engine in much the sameway as in a conventional vehicle. Alternatively, in some hybrid vehiclesand in most electric vehicles, the traditional accessories are replacedwith a wholly electric version of the accessory to perform the samefunction, such as an electric air conditioning system or an electricallypowered compressed air brake system.

In implementing either of the above solutions to power vehicleaccessories, however, inefficiencies are introduced into a vehicle.These inefficiencies may affect the cost of the vehicle, the performanceof the vehicle, or both. For example, if a hybrid or electric vehicleincludes electric versions of one or more accessories, the inefficiencyintroduced in the hybrid vehicle is in the overall cost of the vehicle.The increased cost arises because the electric version of an accessorymust initially be developed and tested. Additionally, the cost of theelectric version of the accessory will typically remain high over aperiod of one to several years because vehicles which use the electricversion of the accessory do not have the high production quantities ofconventional vehicles.

Conversely, if a hybrid vehicle implements a vehicle accessory in thetraditional manner, i.e., powered directly from an internal combustionengine, the vehicle will experience inefficiencies in fuel economy. Theinefficiencies arise when the internal combustion engine provides powerdirectly to the accessories and the electric motor and/or the batteriesdo not require power. During these periods, the engine necessarilyconsumes fuel to provide the power required by the accessories. Anyexcess power generated by the engine, however, is lost because it cannotbe otherwise used or stored by the vehicle.

Series and parallel hybrid-hydraulic drive systems for heavy-dutyvehicles have been developed by Eaton Corporation, Dana Corporation,Permo Drive, and others, but none of these developments have includedseparate hydraulically driven accessories.

SUMMARY OF THE INVENTION

Accordingly, as aspect of the present invention involves a vehicle powersystem for a heavy-duty hybrid vehicle including an engine compartmentand a drive shaft. The vehicle power system includes a main power unitconfigured to supply a DC power to the heavy-duty hybrid vehicle andlocated in the engine compartment; an electric propulsion motor topropel the heavy-duty hybrid vehicle using the drive shaft; a DC buselectrically coupled with the main power unit, the DC bus configured toreceive the DC power from the main power unit; a vehicle accessorytraditionally powered directly from an internal combustion engine of aconventional heavy-duty vehicle and requiring more than 1 kilowatt ofpower, the vehicle accessory including at least one of a compressor anda pump; an electric accessory motor including the following: a) theelectric accessory motor is separate from the electric propulsion motor,b) the electric accessory motor is electrically coupled with the DC busand mechanically coupled with the vehicle accessory, c) the electricaccessory motor is configured to supply power to the vehicle accessory,d) the electric accessory motor and the vehicle accessory are carried bythe heavy-duty vehicle either inside or outside of the enginecompartment; and at least one of an ultracapacitor pack and a fly wheelcoupled with the DC bus, the at least one of an ultracapacitor pack anda fly wheel configured to store power when the main power unit is on andsupply power in place of the main power unit when the main power unit isoff.

The one or more vehicle accessories may be located either inside oroutside the engine compartment. When located inside the enginecompartment the accessories may be separated from the hot areas of theengine compartment by one or more heat shields located between the heatsource and the accessory.

Another aspect of the invention involves a vehicle power system for aheavy-duty hybrid vehicle including an engine compartment and a driveshaft. The vehicle power system includes a main power unit configured tosupply a DC power of more than 42 volts to the heavy-duty hybrid vehicleand located in the engine compartment; an electric propulsion motor topropel the heavy-duty hybrid vehicle using the drive shaft; a DC buselectrically coupled with the main power unit, the DC bus configured toreceive the DC power from the main power unit; a vehicle accessorytraditionally powered directly from an internal combustion engine of aconventional heavy-duty vehicle and requiring more than 1 kilowatt ofpower, the vehicle accessory including at least one of a compressor anda pump; an electric accessory motor including the following: a) theelectric accessory motor is separate from the electric propulsion motor,b) the electric accessory motor is electrically coupled with the DC busand mechanically coupled with the vehicle accessory, c) the electricaccessory motor is configured to supply power to the vehicle accessory,d) the electric accessory motor and the vehicle accessory are carried bythe heavy-duty vehicle either inside or outside of the enginecompartment; a vibration dampening structure that the electric accessorymotor and vehicle accessory are mounted to, the vibration dampeningstructure configured to be mounted to the heavy-duty hybrid vehicle; andat least one of an ultracapacitor pack and a fly wheel coupled with theDC bus, the at least one of an ultracapacitor pack and a fly wheelconfigured to store power when the main power unit is on and supplypower in place of the main power unit when the main power unit is off.

A further aspect of the invention involves a vehicle power system for aheavy-duty hybrid-hydraulic vehicle including an engine compartment anda drive shaft. The vehicle power system includes a primary pumpconfigured to pump high-pressure oil; a main power unit configured topower the primary pump and located in the engine compartment; ahydraulic motor driven by the primary pump to propel the heavy-dutyhybrid-hydraulic vehicle using the drive shaft either separately or incombination with the main power unit; a vehicle accessory traditionallypowered directly from an internal combustion engine of a conventionalheavy-duty vehicle and requiring more than 1 kilowatt of power; ahydraulic accessory motor including the following: a) the hydraulicaccessory motor is separate from the hydraulic motor, b) the hydraulicaccessory motor is mechanically coupled with the vehicle accessory, c)the hydraulic accessory motor is configured to supply power to thevehicle accessory, d) the hydraulic accessory motor and the vehicleaccessory are carried by the heavy-duty hybrid hydraulic vehicle eitherinside or outside of the engine compartment; and an accumulaterconfigured to receive and store high-pressure oil when the main powerunit is on and supply high-pressure oil to the hydraulic accessory motorto drive the hydraulic accessory motor when the main power unit is off.

The types of vehicle accessories that may be driven using the system ofthe present invention include; but not by way of limitation;compressors, such as brake air compressors, charge air compressors, orair conditioning compressors, hydraulic pumps, such as those used forpower steering or other heavy-duty hydraulic equipment; other pumps,such as water pumps, oil pumps, fuel pumps, and vacuum pumps; andcooling fans, such as radiator fans and air conditioning blowers. Eachof these types of vehicle accessories has operational power requirementsthat exceed 1 kilowatt, and each may be of the same type used inconventional vehicles that are powered by internal combustion engines.

Other aspects, advantages, and novel features of the invention, willbecome apparent from the following Detailed Description of PreferredEmbodiments, when considered in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present inventions taught herein areillustrated by way of example, and not by way of limitation, in thefigures of the accompanying drawings, in which:

FIGS. 1 a-1 c schematically illustrate systems of driving vehicleaccessories according to the prior art;

FIG. 2 schematically illustrates a system of driving vehicle accessoriesin accordance with an embodiment of the present invention;

FIGS. 3 a and 3 b illustrate a mounting structure for two vehicleaccessories, a scroll air compressor and a hydraulic pump, driven by asingle accessory motor;

FIG. 4 schematically illustrates a system of driving vehicle accessoriesin accordance with another embodiment of the present invention;

FIG. 5 is a perspective view of a mounting structure for two vehicleaccessories, a scroll air compressor and a hydraulic pump, driven byseparate accessory motors;

FIG. 6 is an exploded view of a gear assembly used to couple a vehicleaccessory to an accessory motor; and

FIG. 7 schematically illustrates a system of driving vehicle accessoriesin a refuse collection truck in accordance with another embodiment ofthe present invention.

FIG. 8 schematically illustrates a system of driving heavy-dutyhydraulic driven vehicle accessories in accordance with a serieshybrid-hydraulic drive system as a further embodiment of the presentinvention.

FIG. 9 schematically illustrates a system of driving heavy-dutyhydraulic driven vehicle accessories in accordance with a parallelhybrid-hydraulic drive system as a further embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning in detail to the drawings, FIGS. 1 a-c illustrate systems ofdriving vehicle accessories as practiced in the prior art. FIG. 1 aschematically illustrates a conventional vehicle 9 (e.g., a passengercar, a light truck, a heavy-duty vehicle such as a refuse collection‘truck or transit bus, or other type of vehicle) having an internalcombustion engine 10. The internal combustion engine has two outputshafts 12, 14. The first output shaft 12 is coupled to an input shaft 41of a transmission 40 that may be used to propel the vehicle using adrive shaft 42. Alternatively, the power provided to the transmission 40may be directed into a transfer case 45 and used to drive a powertake-off shaft 46. The power take-off shaft 46 may be used, for example,to drive an additional axle in a four-wheel drive vehicle or to drive ahydraulic pump used in conjunction with heavy-duty equipment such as thelift mechanism in a dump truck or a compactor in a refuse collectiontruck.

The second output shaft 14 of the internal combustion engine drivesaccessories 20, 30 using a belt drive assembly. The belt drive assemblycomprises a first pulley 15, affixed to the output shaft 14 of theinternal combustion engine, a belt 16 that connects the first pulley 15to two receiving pulleys 22, 32 that are in turn affixed to input shafts21, 31 of accessories 20, 30, respectively. Additional receiving pulleysand accessories may also be included. The accessories 20, 30 in aconventional vehicle often include, for example, a compressor for an airconditioner or air brakes, a water pump, an alternator to recharge thestarting battery and provide accessory power, or a hydraulic pump forpower steering.

FIG. 1 b schematically illustrates a hybrid vehicle 50 having a paralleldrive system as practiced in the prior art. The parallel hybrid vehicle50 includes an internal combustion engine 10 to drive the accessories20, 30 in the same manner as the conventional vehicle 9 of FIG. 1 a. Theoutput shaft 12 of the internal combustion engine 10 is coupled to aninput shaft 52 of a mechanical coupling 54. The mechanical coupling 54is also coupled to an electric motor 53 with an integrated generator.The electric motor may power the drive shaft 51 using power provided bya battery 60 through an inverter 62 or, alternatively, the internalcombustion engine 10 may power the drive shaft 51 through the mechanicalcoupling 54. When the internal combustion engine 10 powers the driveshaft 51, the generator integrated into the electric motor 50 may beused to store power in the battery 60.

FIG. 1 c schematically illustrates a hybrid vehicle 69 having a seriesdrive system as practiced in the prior art. The series hybrid vehicle 69includes an internal combustion engine 10 to drive the accessories 20,30 in the same manner as the conventional vehicle 9 of FIG. 1 a. Theoutput shaft 12 of the internal combustion engine 10 is coupled to aninput shaft 71 of a generator 70. When driven by the internal combustionengine 10, the generator 70 provides electrical power to a battery 60and an inverter 62. The battery may provide electrical power to theinverter 62 when the generator 70 is not operating. The inverter 62 iselectrically coupled to an electric motor 80 that propels the vehicle 69via a drive shaft 81.

FIG. 2 schematically illustrates an embodiment of a system 100 of aheavy-duty vehicle configured to power vehicle accessories 142, 144, inaccordance with the systems and methods disclosed herein. As usedherein, a heavy-duty vehicle is a vehicle having a gross vehicle weight(GVW) of at least 10,000 lbs. Examples of heavy-duty vehicles that thesystems 100, 200, 300, 400 described herein may be used with include,but not by way of limitation, a tractor, a tow tractor, a tug, a pulltractor, a push-back tractor, a truck (e.g., class 6, class 7, class 8,etc.), a dump truck, a delivery truck, a semi truck, a bobtail truck, aschool bus, a transit bus, a pick-up truck, a shuttle van, arefuse-collection vehicle, a recycling-collection vehicle, and a tramvehicle. In alternative embodiments, the systems 100, 200, 300, 400 areused with vehicles other than heavy-duty vehicles, and, thus, is notlimited to heavy-duty vehicles. In alternative embodiments, system 100is incorporated into a series hybrid vehicle and/or a parallel hybridvehicle, but in further embodiments, system 100 is incorporated intoother types of vehicles. The system 100 has a main power unit 102 withat least one power generating source that provides more than 42 volts ofpower to a high voltage DC power bus 112. The power generating sourcecan comprise an internal combustion engine 104 coupled to a generator108 through a drive shaft 106, a fuel cell 110, a micro-turbine (notshown) or any other appropriate power source.

In one or more embodiments, one or more batteries B, one or moreultracapacitor packs U, and/or one or more flywheels F (hereinafter“power source”) 114 are electrically coupled to the DC power bus 112 tostore power generated by the main power unit 102. The power source 114(e.g., one or more batteries B, one or more ultracapacitor packs U, oneor more flywheels F) also stores power from dynamic electro magneticbraking regeneration. A first inverter 116 is electrically coupled tothe DC power bus 112 to provide AC power to the electric motor 118 thatpropels the hybrid vehicle using a drive shaft 120. Preferably a DC toDC converter 122 is included in system 100 to step the high voltage ofthe DC power bus 112 down to an appropriate level required by lowvoltage accessories that may be included in the hybrid vehicle. Forexample DC to DC converter 122 can be configured to provide 12, 24, or42 volts to various low voltage accessories. In an exemplary embodiment,the vehicle includes one or more electric cooling fans for the engineradiator which were traditionally belt driven from the engine crankshaftor hydraulically powered from an engine power take off to a hydraulicpump and thence to a hydraulic fan motor. In this embodiment the DCpower bus 112 is coupled to the DC to DC converter 122 for powering theone or more cooling fans.

A second inverter 124 is coupled to the DC power bus 112 to provide ACpower to an electric accessory motor 126. The output shaft 128 of theelectric accessory motor 126 drives the vehicle accessories 142, 144using a belt drive assembly 148. The electric accessory motor 126provides a total power output that exceeds the operational powerrequirements of any vehicle accessories 142, 144, and preferably theelectric accessory motor 126 is capable of providing a total poweroutput that exceeds the combined maximum power ratings of the vehicleaccessories 142, 144. The belt drive assembly 148 comprises a firstpulley 130, affixed to the output shaft 128 of the electric accessorymotor 126, a belt 132 that connects the first pulley 130 to tworeceiving pulleys 134, 136, each receiving pulley 134, 136 being affixedto an input shaft 138, 140 of one of the accessories 142, 144.Additional receiving pulleys and accessories may also be included. Theelectrical rating of accessory motor 126 is preferably based upon theoperational power requirements of the accessories affixed to the beltdrive assembly 148.

Examples of vehicle accessories that may be advantageously powered bythe electric accessory motor 126 include, but not by way of limitation,air compressors, air conditioning compressors, oil pumps, fuel pumps,charge air compressors, water pumps, hydraulic pumps, vacuum pumps, orother accessories that have operational power requirements in excess of1 kilowatt. In the case of an air compressor, a piston-type aircompressor can be used, a screw type air compressor can be used, or morepreferably, a scroll-type air compressor can be used. Such accessoriesare traditionally powered directly from the internal combustion enginein a conventional vehicle because of their relatively high powerrequirements.

An advantage to using electric accessory motor 126 is that the internalcombustion engine 104 can be shut down when the vehicle and itsaccessories 142 and 144 are adequately powered by the power source 114(e.g., one or more batteries B, one or more ultracapacitor packs U, oneor more flywheels F). Thus, with the high power accessories 142 and 144being driven by the accessory motor 126, the internal combustion engine104 may be operated less frequently than if the accessories 142 and 144are driven directly from the internal combustion engine 104 whichresults in greater fuel efficiency. Greater fuel efficiency can alsoresult from only using the accessory when required by switching off theelectric accessory motor when the accessory is not required.Additionally, because each of these high power accessories 142 and 144may be of the same shaft driven type typically used in conventionalvehicles, significant savings may be realized in the overall cost of thevehicle. These cost savings arise through economies of scale that arealready in place for the shaft driven version of the high poweraccessories 142 and 144, as compared to the development andmanufacturing infrastructure that exists for entirely electronicversions of these same accessories.

An additional advantage of driving the high power accessories 142 and144 with a separate accessory motor 126 is that the accessories 142 and144 can be affixed to any location on the vehicle. The aforementionedhigh power accessories are often mounted within the engine compartmentin a conventional vehicle. Thus, not only do the accessories 142 and 144share the same compartmental space with the engine, but they also sharethe same dirt, dust, high temperature, and vibrations present within theengine compartment, most of which is created by the internal combustionengine. By powering the vehicle accessories 142 and 144 with a separateaccessory motor 126, the vehicle accessories 142 and 144 can be mountedanywhere on or in the vehicle, thus making the accessories 142 and 144more accessible and removing them from an environment that contributesto wear and tear.

In an alternative embodiment of the system 100, where the system 100 isincorporated into a parallel hybrid vehicle, the electric propulsionmotor 118 is part of a parallel hybrid-electric transmission wherein theelectric propulsion motor 118 assists the mechanical transmission topropel the vehicle using the drive shaft 120.

FIG. 3 a illustrates an accessory motor 150 coupled to a scroll-type aircompressor 152 and a hydraulic pump 154, all of which are affixed to avibration dampening mounting structure 156. The shaft (not shown) of theaccessory motor 150 is accessible from two opposite sides of theaccessory motor. On one side, the accessory motor 150 is mechanicallycoupled to the air compressor 152 using a clutch 158, which can be ofany appropriate type, pulley 160, and belt mechanism 161. With this typeof coupling, the air compressor 152 may be driven at any time simply byengaging the clutch 158. On the opposite side, the mechanical couplingbetween the accessory motor 150 and the hydraulic pump 154 is a directshaft connection. Thus, when the accessory motor 150 is operative,operational power is provided to the hydraulic pump 154. The type ofmechanical coupling is chosen to best serve the needs of the vehiclewith which the accessories are used. Therefore, many alternative typesof mechanical couplings can be employed.

The vibration dampening mounting structure 156 of FIG. 3 a comprises aplate 162 and mounting bolts 164 to affix the plate to the vehicle inthe manner shown in FIG. 3 b. The mounting bolts 164 are vibrationallyisolated from the mounting plate 162 by interposing a vibrationdampening material 166, such as rubber, between the mounting bolts 164and the mounting plate 162. Additionally, each bolt 164 extends througha hole 168 in the mounting plate 162, without having physical contactwith the mounting plate 162, and is affixed to supporting structure 170of the vehicle. Thus, vibrations that would otherwise travel between thevehicle and the accessories are largely absorbed by the vibrationdampening material 166. Other vibration isolation and dampeningtechniques can also be employed. However, robust components may be usedthat would eliminate the requirement for vibration and shock isolation.Even without a vibration dampening mounting structure, a single platemounting structure would have the choice of mounting locations andconnections advantages listed below.

An advantage of having the accessory motor 150 and the accessories 152and 154 affixed to the vibration dampening mounting structure 156 isthat the vibration dampening mounting structure 156 can be affixed tothe vehicle either within the engine compartment or external to theengine compartment. Additionally, the vibration dampening mountingstructure 156 may be mounted at any desired orientation relative to thevehicle because no overly restrictive mechanical connections (i.e., adrive shaft connection) are required. Regardless of where and how thevibration dampening mounting structure 156 is mounted, the electricalcoupling between the electric accessory motor 150 and the DC power bus,e.g., bus 112, is easily accomplished using insulated wires. Otherconnections required by certain accessories, such as a compressed air orpressurized fluid line, are also easily made regardless of where on thevehicle the accessories are affixed.

FIG. 4 schematically illustrates an alternative embodiment of a system200 configured to power vehicle accessories 210, 230, and 250 of aheavy-duty vehicle. In alternative embodiments, the system 200 is usedwith vehicles other than heavy-duty vehicles, and, thus, is not limitedto heavy-duty vehicles.

Preferably, system 200 is incorporated into a series hybrid vehicle. Inan alternative embodiment, system 200 is incorporated into a parallelhybrid vehicle. System 200 includes a main power unit 102 that powers ahigh voltage DC power bus 112. In this example, however, each vehicleaccessory 210, 230, and 250 is driven by a separate accessory motor 212,232, and, 252, respectively. Each motor 212, 232, and 252 draws powerfrom the DC power bus 112. For the first accessory 210, the AC motor 212is preferably integrated with an inverter 214 and electrically coupled,through the inverter 214, to the DC power bus 112. The AC motor 212 alsopreferably includes an output shaft 216 that is connected to an inputshaft 220 of the accessory 210 through a mechanical coupler 218. Themechanical coupler 218 can comprise a pulley and belt mechanism, ashaft-to-shaft coupler, a clutch, or any other type of appropriatemechanical coupler. The mechanical coupler 218 and the AC motor 212 forthe first accessory 210 are also preferably chosen to suit the power andusage requirements of the first accessory 210.

In the example illustrated in FIG. 4, the second accessory 230 is drivenin the same manner as the first accessory 210. An AC motor 232 with anintegrated inverter 234 is electrically coupled to the DC power bus 112.The output shaft 236 of the AC motor 232 drives an input shaft 240 ofthe second accessory 230 through a mechanical coupler 238. Themechanical coupler 238 and the AC motor 232 for the second accessory 230are chosen to suit the power and usage requirements of the secondaccessory 230. Thus, the AC motor 232 driving the second accessory 230may have a different power rating than the AC motor 212 driving thefirst accessory 210.

The third accessory shown in FIG. 4 is a hydraulic pump 250 forheavy-duty hydraulic equipment, for example, such as a refuse compactoror a lift mechanism. An inverter is preferably electrically coupled tothe DC power bus 112 and to an AC motor 252 to provide power to the ACmotor 252. The output shaft 256 of the AC motor 252 preferably drivesthe input shaft 260 of the hydraulic pump 250 through a mechanicalcoupler 258. The mechanical coupler 258 and the AC motor 252 for thehydraulic pump 250 are preferably chosen to suit the power and usagerequirements of the hydraulic pump 250. Additional AC motors may becoupled to the DC power bus to drive additional accessories as needed.

Examples of vehicle accessories that may be advantageously powered bythe electric accessory motors 212, 232, and 252 include, but not by wayof limitation, air compressors, air conditioning compressors, oil pumps,fuel pumps, charge air compressors, water pumps, hydraulic pumps, vacuumpumps, or other accessories that have operational power requirements inexcess of 1 kilowatt. In the case of an air compressor, a piston-typeair compressor can be used, a screw type air compressor can be used, ormore preferably, a scroll-type air compressor can be used. Suchaccessories are traditionally powered directly from the internalcombustion engine in a conventional vehicle because of their relativelyhigh power requirements.

In an alternative embodiment of the system 200, where the system 200 isincorporated into a parallel hybrid vehicle, the electric propulsionmotor 118 is part of a parallel hybrid-electric transmission wherein theelectric propulsion motor 118 assists the mechanical transmission topropel the vehicle using the drive shaft 120.

FIG. 5 illustrates a multi-accessory motor implementation comprisingfirst and second accessory motors 270 and 272 coupled to a scroll-typeair compressor 274 and a hydraulic pump 276, respectively. Both motors270 and 272, as well as compressor 274 and pump 276, are affixed to avibration dampening mounting structure 278 or a hard mounting structureas determined by the robustness and cost of the components. The firstaccessory motor 270 is mechanically coupled to the air compressor 274using a gear assembly 280. The gear assembly 280 is illustrated in FIG.6. The gear assembly 280 comprises first and second gears 282, 284, asleeve 286, and a counter-mass 288. Counter-mass 288 is specificallyconfigured to be used with the sleeves 286 and gears 282, 284. Thus,counter-mass 288 preferably replaces a standard counter-mass that isnormally used with a scroll air compressor. The first gear 282 isaffixed to the output shaft of the accessory motor 270, and the secondgear 284 is affixed to the input shaft of the scroll air compressor 274.

The sleeve 286 is preferably made out of a flexible material such asneoprene. A first side 286 a of the sleeve 286 is preferably formed tomate with the teeth of the first gear 282 and the second side 286 b ofthe sleeve 286 is preferably formed to mate with the teeth of the secondgear 284. The teeth of each gear preferably have a depth of at least 3.0mm, and even more preferably of at least 5.0 mm. The sleeve 286 ispreferably manufactured to have a slightly smaller diameter than eachgear 282, 284, requiring the material to be slightly stretched whencoupled to the gears. As such, the sleeve 286 will fit snugly about thegears 282, 284 to provide a coupling that will not slip under mostnormal operating conditions. When assembled, a gap is preferably leftwithin the sleeve 286 between the opposing ends of the first and secondgears 282, 284. Thus, the flexibility of the sleeve 286 and the gearspacing within the sleeve 286 compensate for shaft misalignments thatmay occur during normal operation.

Returning to FIG. 5, the second accessory motor 272 is mechanicallycoupled to the hydraulic pump 276 using a direct shaft-to-shaftconnector 290. The accessory motors 270, 272, the hydraulic pump 276,and the air compressor 274 are affixed to a frame 292. The frame 292 isaffixed to the vehicle using vibration isolation techniques.

FIG. 7 schematically illustrates an embodiment of system 300 configuredto supply power to accessories within a heavy-duty vehicle (e.g., refusecollection vehicle). In alternative embodiments, the system 300 is usedwith vehicles other than heavy-duty vehicles, and, thus, is not limitedto heavy-duty vehicles.

Preferably, system 300 is incorporated into a series hybrid vehicle. Inan alternative embodiment, system 300 is incorporated into a parallelhybrid vehicle.

The accessories comprise a scroll air compressor 326, a power steeringpump 328, and a hydraulic pump 354. In this example, compressor 326 andpump 328 are both driven by electric accessory motor 324, whilehydraulic pump 354 is driven by electric accessory motor 346. Thevehicle comprises a compressed natural gas engine 302, such as thosemanufactured by John Deere of Moline, Ill., or Cummins Westport, havingan output shaft 304 that is coupled to a generator 306. The generator306 generates power on a high voltage DC power bus 308. In the exampleillustrated in FIG. 3, a power source 310 (e.g., one or more batteriesB, one or more ultracapacitor packs U, one or more flywheels F), a powerconverter 320, and a plurality of power inverters 312, 322, 344 arecoupled to and receive power from the DC power bus 308. The power source310 (e.g., one or more batteries B, one or more ultracapacitor packs U,one or more flywheels F) also stores power from dynamic electro magneticbraking regeneration. The power converter 320 converts the high voltageDC power to low voltage DC power for use by low voltage accessories asexplained with regard to converter 122. In an exemplary embodiment, thevehicle includes one or more electric cooling fans for the engineradiator, which were traditionally belt driven from the enginecrankshaft or hydraulically powered from an engine power take off to ahydraulic pump, and, thence, to a hydraulic motor to rotate the fan. Inthis embodiment the DC power bus 308 is coupled to the power converter320 for powering the one or more cooling fans. Power inverter 312converts the high voltage DC power to AC power for use by an electricmotor 316 that propels the vehicle through a drive shaft 318.

Power inverter 322 converts the high voltage DC power to approximately115 volt AC power. This second power inverter 322 powers a constantspeed AC permanent magnet motor 324 and also provides 115 volt AC powerto those vehicle accessories that require such. In this example, the ACmotor 324 drives an output shaft 330 that is coupled to a pulley 332. Abelt couples the pulley 332 to two receiving pulleys 336 and 338 thatare coupled to the input shafts 340 and 342 of the scroll air compressor326 and the power steering pump 328, respectively. The scroll aircompressor 326 provides compressed air for the braking system of thevehicle and the power steering pump 328 provides pressurized hydraulicfluid for the power steering system.

Power inverter 344 converts the high voltage DC power for use by an ACelectric motor 346. The output shaft 348 of the AC motor 346 ispreferably coupled to an input shaft 352 of a hydraulic pump 354 througha mechanical coupler 350. The hydraulic pump 354 can be a heavy-dutypump that provides, for example, the necessary fluid pressurization tooperate the lift arms and compactor of the refuse collection vehicle300. The AC motor 346 and power inverter 344 are thus selectedappropriately based upon the power requirements of the hydraulic pump354.

Examples of vehicle accessories that may be advantageously powered bythe electric accessory motors 324, 346 include, but not by way oflimitation, air compressors, air conditioning compressors, oil pumps,fuel pumps, charge air compressors, water pumps, hydraulic pumps, vacuumpumps, or other accessories that have operational power requirements inexcess of 1 kilowatt. In the case of an air compressor, a piston-typeair compressor can be used, a screw type air compressor can be used, ormore preferably, a scroll-type air compressor can be used. Suchaccessories are traditionally powered directly from the internalcombustion engine in a conventional vehicle because of their relativelyhigh power requirements.

The scroll air compressor 326, the power steering pump 328, and theassociated AC motor 324 can be mounted to a common vibration dampeningmounting structure (not shown) and can be advantageously affixed to anyappropriate part of the vehicle. The hydraulic pump 354 and itsassociated AC motor 346 are preferably mounted on another vibrationdampening mounting structure (not shown) and can also be advantageouslyaffixed to any appropriate part of the vehicle. Factors that may beconsidered in determining where to affix the two vibration dampeningmounting structures include, for example, isolation from undesirableenvironments, ease of access in the event repairs become necessary, andconvenience based upon the function of each accessory, among others.

Thus, as mentioned, an advantage to the systems and methods disclosedherein is that the electric accessory motors can be powered from powersource 114 (e.g., one or more batteries B, one or more ultracapacitorpacks U, one or more flywheels F). If the main power unit 102 comprisesan internal combustion engine, then inefficiencies in fuel economy canbe reduced, because the internal combustion engine does not need tosupply power to accessories 142 and 144 when they do not require power.Additionally, because the systems and methods described herein can beimplemented with conventional vehicle accessories, cost inefficienciesin hybrid and electric vehicles may be overcome. Accordingly, thesystems and methods described herein are not limited to any particulartype of vehicle. Rather, the systems and methods described herein can beimplemented in any type of vehicle.

In an alternative embodiment of the system 300, where the system 300 isincorporated into a parallel hybrid vehicle, the electric propulsionmotor 316 is part of a parallel hybrid-electric transmission wherein theelectric propulsion motor 316 assists the mechanical transmission topropel the vehicle using the drive shaft 318.

With reference to FIGS. 8 and 9, a system 400 of driving heavy-dutyhydraulically driven vehicle accessories in accordance with a furtherembodiment of the present invention will be described. The system 400 isa hydraulically driven accessory power system for the serieshybrid-hydraulic heavy-duty vehicle drive system shown in FIG. 8 and theparallel hybrid-hydraulic heavy-duty vehicle drive system shown in FIG.9. In alternative embodiments, the system 400 is used with vehiclesother than heavy-duty vehicles, and, thus, is not limited to heavy-dutyvehicles.

The system 400 includes one or more high-pressure hydraulic pumps/motors410. As pumps, the one or more high-pressure hydraulic pumps/motors 410use mechanical energy to deliver high-pressure oil. As motors, the oneor more high-pressure hydraulic pumps/motors 410 accept high-pressureoil and deliver mechanical energy to drive the heavy-duty vehicle viadrive shaft 120. One or more accumulators 430 function as energy storagedevices for the high-pressure oil. An oil cooler (not shown), mayinclude lubrication and cooling pumps, maintains the proper operatingtemperature of the oil in the system 400. In the parallelhybrid-hydraulic drive system of FIG. 9 a power drive coupler 450combines torque from the engine 104/transmission 105 input and outputshafts and the hydraulic pump/motor unit(s) 410. A controller 460manages all the functions of the hydraulic pump/motor unit(s) 410 andthe power drive coupler unit 450. The controller 460 controls thehydraulic pump/motor unit(s) 410, determines when to switch drivingbetween the hydraulic pump/motor unit(s) 410 and engine 104, andmonitors the function of the power drive coupler unit 450. Inalternative embodiments, the controller 460 provides other/alternativecontrol functions.

In operation the hydraulic pump/motor 410 transfers high pressure oilfrom one accumulator 430 to another depending on whether the vehicle isaccelerating or decelerating or moving in forward or in reverse. Inalternative embodiments one of the accumulators 430 is an oil reservoir425. One or more hydraulic accessory motor(s) 465 are in communicationwith the high pressure accumulator(s) 430 through the high pressure line480 for driving the hydraulic accessory motor(s) 465, which in, in turn,power one or more accessories 470. In FIG. 8 and FIG. 9 the twoaccumulator 410 lines are logically “OR”ed to indicate that highpressure oil is connected to the hydraulic accessory motor(s) 465. Afterthe high pressure oil passes through the hydraulic accessory motor thenow low pressure oil passes to an oil reservoir 425 that is used toreplenish the oil required for the hydraulic pump/motor 410.

One or more of the above-described components may be mounted on one ormore vibration dampening mounting structures.

In series hydraulic hybrid use, engine 104 (e.g., diesel engine, CNGengine, internal combustion engine) powers the hydraulic pump/motordrive unit 410. These motor(s) 410 drive the output shaft 120 at allspeeds. In parallel hydraulic hybrid use the motor(s) 410 drive theoutput shaft at low speeds and at higher speeds, the power drive couplerunit 450 switches to direct mechanical drive powered by the engine 104,bypassing the hydraulic unit(s) 410.

The power drive coupler unit 450 recovers braking energy with the motors410 becoming pumps that pump high-pressure oil into the accumulator(s)430.

The stored energy in the accumulator(s) 430 is used for driving themotor(s) 410 and for driving the hydraulic accessory motor(s) 465. Thehydraulic accessory /motor(s) 465, in turn, powers one or moreaccessories 470 via belt drive assembly 148. The controller 460 also hasthe engine 104 drive the hydraulic pump 410 as necessary to maintainhigh pressure oil in the accumulator 430 to power the hydraulicaccessory motor 465.

Examples of vehicle accessories that may be advantageously powered bythe hydraulic accessory motor(s) 465 include, but not by way oflimitation, air compressors, air conditioning compressors, oil pumps,fuel pumps, charge air compressors, water pumps, hydraulic pumps, vacuumpumps, or other accessories that have operational power requirements inexcess of 1 kilowatt. In the case of an air compressor, a piston-typeair compressor can be used, a screw type air compressor can be used, ormore preferably, a scroll-type air compressor can be used. Suchaccessories are traditionally powered directly from the internalcombustion engine in a conventional vehicle because of their relativelyhigh power requirements.

In an alternative embodiment of the system 400, where the system 400 isincorporated into a parallel hydraulic hybrid vehicle, as depicted inFIG. 9, the motor(s) 410 are part of a parallel hybrid-hydraulictransmission wherein the motor(s) 410 assist the mechanical transmissionto propel the vehicle using the drive shaft 120.

While embodiments and implementations of the invention have been shownand described, it should be apparent that many more embodiments andimplementations are within the scope of the invention. Accordingly, theinvention is not to be restricted, except in light of the claims andtheir equivalents.

1. A vehicle power system for a heavy-duty hybrid vehicle including anengine compartment and a drive shaft, comprising: a main power unitconfigured to supply a DC power to the heavy-duty hybrid vehicle andlocated in the engine compartment; an electric propulsion motor topropel the heavy-duty hybrid vehicle using the drive shaft; a DC buselectrically coupled with the main power unit, the DC bus configured toreceive the DC power from the main power unit; a vehicle accessorytraditionally powered directly from an internal combustion engine of aconventional heavy-duty vehicle and requiring more than 1 kilowatt ofpower, the vehicle accessory including at least one of a compressor anda pump; an electric accessory motor including the following: a) theelectric accessory motor is separate from the electric propulsion motor,b) the electric accessory motor is electrically coupled with the DC busand mechanically coupled with the vehicle accessory, c) the electricaccessory motor is configured to supply power to the vehicle accessory,d) the electric accessory motor and the vehicle accessory are carried bythe heavy-duty vehicle either inside or outside of the enginecompartment; and at least one of an ultracapacitor pack and a fly wheelcoupled with the DC bus, the at least one of an ultracapacitor pack anda fly wheel configured to store power when the main power unit is on andsupply power in place of the main power unit when the main power unit isoff or in addition to the main power unit when the main power unit ison.
 2. The vehicle power system of claim 1, wherein the at least one ofan ultracapacitor pack and a fly wheel is configured to store power fromdynamic electromagnetic braking regeneration.
 3. The vehicle powersystem of claim 1, further comprising electric cooling fans that weretraditionally belt driven from the engine drive shaft or hydraulicallypowered from an engine power take off to a hydraulic pump, and a DC toDC converter electrically coupled with the DC bus, the DC to DCconverter configured to convert the DC power supplied by the main powerunit to a DC power for use by the electric cooling fans.
 4. The vehiclepower system of claim 1, further comprising electric cooling fans thatwere traditionally belt driven from the engine drive shaft orhydraulically powered from an engine power take off to a hydraulic pump,and an inverter electrically coupled with the DC bus, the inverterconfigured to convert the DC power supplied by the main power unit to anAC voltage for use by the electric cooling fans.
 5. A vehicle powersystem for a heavy-duty hybrid vehicle including an engine compartmentand a drive shaft, comprising: a main power unit configured to supply aDC power of more than 42 volts to the heavy-duty hybrid vehicle andlocated in the engine compartment; an electric propulsion motor topropel the heavy-duty hybrid vehicle using the drive shaft; a DC buselectrically coupled with the main power unit, the DC bus configured toreceive the DC power from the main power unit; a vehicle accessorytraditionally powered directly from an internal combustion engine of aconventional heavy-duty vehicle and requiring more than 1 kilowatt ofpower, the vehicle accessory including at least one of a compressor anda pump; an electric accessory motor including the following: a) theelectric accessory motor is separate from the electric propulsion motor,b) the electric accessory motor is electrically coupled with the DC busand mechanically coupled with the vehicle accessory, c) the electricaccessory motor is configured to supply power to the vehicle accessory,d) the electric accessory motor and the vehicle accessory are carried bythe heavy-duty vehicle either inside or outside of the enginecompartment; a vibration dampening structure that the electric accessorymotor and vehicle accessory are mounted to, the vibration dampeningstructure configured to be mounted to the heavy-duty hybrid vehicle; andat least one of an ultracapacitor pack and a fly wheel coupled with theDC bus, the at least one of an ultracapacitor pack and a fly wheelconfigured to store power when the main power unit is on and supplypower in place of the main power unit when the main power unit is off orin addition to the main power unit when the main power unit is on. 6.The vehicle power system of claim 5, wherein the at least one of anultracapacitor pack and a fly wheel is configured to store power fromdynamic electromagnetic braking regeneration.
 7. The vehicle powersystem of claim 5, further comprising electric cooling fans that weretraditionally belt driven from the engine drive shaft or hydraulicallypowered from an engine power take off to a hydraulic pump, and a DC toDC converter electrically coupled with the DC bus, the DC to DCconverter configured to convert the DC power supplied by the main powerunit to a DC power for use by the electric cooling fans.
 8. The vehiclepower system of claim 5, further comprising electric cooling fans thatwere traditionally belt driven from the engine drive shaft orhydraulically powered from an engine power take off to a hydraulic pump,and an inverter electrically coupled with the DC bus, the inverterconfigured to convert the DC power supplied by the main power unit to anAC voltage for use by the electric cooling fans.
 9. A vehicle powersystem for a heavy-duty hybrid-hydraulic vehicle including an enginecompartment and a drive shaft, comprising: a primary pump configured topump high-pressure oil; a main power unit configured to power theprimary pump and located in the engine compartment; a hydraulicpropulsion motor driven by the primary pump to propel the heavy-dutyhybrid-hydraulic vehicle using the drive shaft; a vehicle accessorytraditionally powered directly from an internal combustion engine of aconventional heavy-duty vehicle and requiring more than 1 kilowatt ofpower; a hydraulic accessory motor including the following: a) thehydraulic accessory motor is separate from the hydraulic propulsionmotor, b) the hydraulic accessory motor is mechanically coupled with thevehicle accessory, c) the hydraulic accessory motor is configured tosupply power to the vehicle accessory, d) the hydraulic accessory motorand the vehicle accessory are carried by the heavy-duty hybrid hydraulicvehicle either inside or outside of the engine compartment; and anaccumulator configured to receive and store high-pressure oil when themain power unit is on and supply high-pressure oil to the hydraulicaccessory motor to drive the hydraulic accessory motor when the mainpower unit is off.
 10. The vehicle power system of claim 9, wherein theaccumulator is configured to receive and store high-pressure oil frombraking regeneration.